libellous vs calumniatory

libellous and calumniatory both are adjectives.

Word	Noun	Adjective	Verb	Adverb
libellous	No	Yes	No	No
calumniatory	No	Yes	No	No

As adjectives, libellous and calumniatory are synonyms defined as:

libellous and calumniatory: (used of statements) harmful and often untrue; tending to discredit or malign

Other synonyms of libellous include calumnious, defamatory, denigrating, denigrative, denigratory, libelous, slanderous.

libellous (adjective)	calumniatory (adjective)
(used of statements) harmful and often untrue; tending to discredit or malign	(used of statements) harmful and often untrue; tending to discredit or malign